STEREO Weekly Meeting Minutes for 2010-04-27 (Week 17) ANNOUNCEMENTS ------------- * APL is looking into developing a new tool to show when the insitu instrument partitions may potentially reach or exceed capacity. See below for details. INSTRUMENT and SPACECRAFT STATUS -------------------------------- * All subsystems on both spacecraft are nominal. DISCUSSION AND OPERATIONS CONSTRAINTS ------------------------------------- Week 16 * A transmitter anomaly occured at 12:32 UT during the station 15 pass for Ahead on day 109 (Apr 19). This caused the receiver to lose lock at 12:51 UT, after the round-trip light time. This resulted in the loss of several minutes of SSR data. * The planned 70 meter support on station 43 for Ahead on day 112 (Apr 22) was changed to a 34 meter station because of problem with the Voyager 2 spacecraft. The track time was increased to 7 hours, and all data were recovered. This required commanding in the blind to switch downlink rates. * Switched to 7 hour DSN tracks for Ahead starting Apr 19. * The new macros for the 240 and 120 kbps telemetry rates were tested on Ahead on day 109 (Apr 19). * The 29th momentum dump was carried out on Ahead on day 111 (Apr 21) starting at 16:00 UT. A delta-V of 0.074 m/s was imparted. * Command uplink was late during the station 34 pass for Behind on day 112 (Apr 22) due to the transmitter going offline at 02:20 UT. Uplink was reestablished at 02:56 UT. This resulted in the loss of 26 minutes of command and tracking data, and several minutes of SSR data. * On days 113, 114, and 115 (Apr 23-25), the insitu instruments began overwriting. This was due to the Behind schedule being short 9 hours of track time for the week. Behind is currently lined up with Mars, and with the Dawn and MUSES-C missions. SOHO is currently running an MDI continuous campaign, and one DSN station is down. These all put pressure on the DSN schedule. Additional shortfalls are expected to occur occasionally for Behind until the September/October time period. The Ahead schedule looks okay for the next few months, but will be lined up with Mars next year. * There was discussion about what steps the insitu instruments might take to be more proactive about planning for times when the partitions might reach or exceed capacity. In-situ instrument teams will consider the trade-off between a temporary or constant reduction in their overall instrument science return and the data gaps that are a result of occasional reduced total downlink. APL will do more to publicize anticipated shortfalls in advance, and is looking into developing a new tool to highlight when shortfalls may occur for the insitu instruments. * Currently, when MOps sees that the partitions are close to full, they will move pointers during a pass. They are looking into ways to make this more automated. * MOps permanent release 1.1.3 was uploaded to the C&DH EEPROM on Behind on day 112 (Apr 22). This removes double playback from the 720 kbps telemetry rate. * The average daily SSR downlink was 5.8 gigabits for Ahead, and 4.4 gigabits for Behind. Week 17 * Ahead switched to 240 kbps rate yesterday (Apr 26). * A SECCHI-driven GT calibration offpoint is planned for Wednesday, Apr 28, starting at 7:30 UT on both spacecraft. The amount of offpoint should be on the order of an arc minute, and the activity lasts about 90 minutes. * Release 1.1.3 will be uploaded to Ahead on Wednesday (Apr 28). * Ahead will have more hours than required during the week. * Uplink was late at 20:05 UT during the Behind pass yesterday (Apr 26). Uplink was re-established, and pointers were moved backward to not lose any data. All partitions were emptied. * The 23rd momentum dump will be carried out on Behind this afternoon (Apr 27), starting at 20:30 UT. * MOps will begin using new DSN tables on Thursday (Apr 29). * Behind has 1 additional hour than required during the week. Pointers will be moved throughout to avoid losing data. Week 18 * An SDO/EVE calibration sounding rocket launch is scheduled for Monday, May 3. This affected the Behind schedule due to SOHO support for the launch. More time has been negotiatied for STEREO to mitigate the schedule changes. * SECCHI/HI calibration offpoints are scheduled for Thursday, May 6, at 09:35 UT on Ahead, and 17:50 UT on Behind. The maximum offset is about 1.5 degrees about the spacecraft Y axis, and the activity lasts about 90 minutes. * Both Ahead and Behind are short about 1 hour of DSN time during the week. Week 19 * 70 meter support is planned for both spacecraft on Monday, May 10, using Madrid station 63 for Ahead, and Canberra station 43 for Behind. These will be carried out at 720 kbps. * There are a number of short tracks for Ahead. * Ahead is about 2.7 hours short of track coverage during the week, while Behind is about even. Week 20 * Events on other missions are affecting the STEREO DSN schedule during the week. The Japanese JAXA mission Akatsuki (PLANET-C, previously known as Venus Climate Orbiter) is scheduled for launch on Monday, May 17, at 21:44 UT. Because of this, the Ahead pass on Thursday, May 20 will follow a 34 hour gap. Pointers will be moved for this and the following tracks until the buffers can be cleared. * There will be a 70 meter downlink on station 43 for the Ahead spacecraft on May 23. This will be carried out at 720 kbps. Because the pass duration is just 2 hours, only science data will be downlinked. * The overall pass schedule for Ahead is about even. * Ahead will be at perihelion on May 18. The 13th SECCHI stepped calibration roll is scheduled for 00:25 on that day. The system momentum is expected to be ~2 N-m-s. * The 39 hour gap between Behind tracks from Monday to Tuesday has been shortened to 31 hours due to the addition of a track. There is still a 35.5 hour gap on Behind between Wednesday and Thursday. The pass on Thursday is only 2.7 hours long. Pointers will be moved for these and the following tracks until the buffers can be cleared. * Overall, the amount of track time for Behind is about even during the week. However, because of the large gaps, there is still a potential for data loss for the insitu instruments. COORDINATED OBSERVATIONS ------------------------ ------------------------------------------------------------------------------- Scheduled activities for Week 17: M Apr 26 (116) Ahead: Switch downlink rate to 240 kbps T Apr 27 (117) Behind: Momentum dump, 20:30 UT W Apr 28 (118) Both: SECCHI-driven GT calibration offpoint, 7:30 UT T Apr 29 (119) F Apr 30 (120) S May 01 (121) S May 02 (122) ------------------------------------------------------------------------------- Scheduled activities for Week 18: M May 03 (123) EVE calibration sounding rocket launch, 18:12 UT T May 04 (124) EVE calibration sounding rocket launch backup, 18:12 UT W May 05 (125) T May 06 (126) SECCHI HI stray light cal. offpoint, Ahead: 09:35, Behind: 17:50 F May 07 (127) S May 08 (128) S May 09 (129) ------------------------------------------------------------------------------- Scheduled activities for Week 19: M May 10 (130) Both: 720 kbps downlink T May 11 (131) W May 12 (132) T May 13 (133) F May 14 (134) S May 15 (135) S May 16 (136) ------------------------------------------------------------------------------- Scheduled activities for Week 20: M May 17 (137) T May 18 (138) Ahead: SECCHI stepped calibration roll, 00:25 UT Ahead: Perihelion, 18:57 UT Behind: 31 hour gap between passes W May 19 (139) T May 20 (140) Ahead: 34 hour gap between passes F May 21 (141) Behind: 35.5 hour gap between passes S May 22 (142) S May 23 (143) Ahead: 720 kbps downlink on station 43 ------------------------------------------------------------------------------- Upcoming events: 2010: ICAL-001: May 3-7 SECCHI Stepped calibration rolls Ahead: Aug 10, Nov 2 Behind: Jul 13, Oct 12 * Jun 8 SUMI sounding rocket launch http://adsabs.harvard.edu/abs/2008AGUSMSP51B..01A * Jul 8,15 EIT shutterless (TBC) * Jul 11 Total solar eclipse http://eclipse.gsfc.nasa.gov/SEmono/TSE2010/TSE2010.html * Jul 14 Both: HGA calibration * Aug 23 Ahead: End use of 720 kbps on 70 m DSN subnet * Sep 6 Behind: End use of 720 kbps on 70 m DSN subnet * Sep 7 Both: Begin 8 hour daily DSN tracks * Sep 13 Both: Switch downlink rate to 160 kbps * Nov 15 Behind: Switch downlink rate to 120 kbps 2011: * Jan 12 Both: HGA calibration * Feb 6 STEREO spacecraft at 180 degree separation * Mar 18 Messenger - Mercury orbital insertion * Apr 11 Ahead: Switch downlink rate to 120 kbps * Jul DAWN - Vesta arrival * Jul 13 Both: HGA calibration * Sep 19 Behind: Switch downlink rate to 96 kbps * Sep 26 Ahead: Switch downlink rate to 96 kbps 2012: * Jan 9 Behind: End use of 480 kbps on 70 m DSN subnet * Jan 11 Both: HGA calibration * Jun 25 Ahead: End use of 480 kbps on 70 m DSN subnet * Jul DAWN - Vesta departure * Jul 11 Both: HGA calibration * Aug 20 Both: Switch downlink rate to 30 kbps * Nov 13 Total solar eclipse, south Pacific 2013: * Nov 25 Behind: End use of 360 kbps on 70 m DSN subnet * Dec 12 Ahead: Mercury transit 2014: * Apr 29 Behind: Mercury transit 2015: * Feb DAWN - Ceres arrival * Jan 10 - Apr 12 Behind: Spacecraft behind Sun * Feb 17 - Aug 2 Ahead: Spacecraft behind Sun * May 25 Ahead: End use of 360 kbps on 70 m DSN subnet * Aug 10 Ahead: Begin use of 360 kbps on 70 m DSN subnet * Jul 23 - Nov 10 Behind: Spacecraft behind Sun * Jul DAWN - End of nominal mission 2016: 2017: 2018: * Mar 5 Ahead: Mercury transit